How, then, is a living being conceived? Is the substance of both body and soul formed together at one and the same time? Or does one of them precede the other in natural formation? We indeed maintain that both are conceived, and formed, and perfectly simultaneously, as well as born together; and that not a moment’s interval occurs in their conception, so that a prior place can be assigned to either. Judge, in fact, of the incidents of man’s earliest existence by those which occur to him at the very last. As death is defined to be nothing else than the separation of body and soul, life, which is the opposite of death, is susceptible of no other definition than the conjunction of body and soul. If the severance happens at one and the same time to both substances by means of death, so the law of their combination ought to assure us that it occurs simultaneously to the two substances by means of life. Now we allow that life begins with conception, because we contend that the soul also begins from conception; life taking its commencement at the same moment and place that the soul does. Thus, then, the processes which act together to produce separation by death, also combine in a simultaneous action to produce life.

Tertullian. 1885. “A Treatise on the Soul.” In Latin Christianity: Its Founder, Tertullian, edited by Alexander Roberts, James Donaldson, and A. Cleveland Coxe, translated by Peter Holmes, 3:207–8. The Ante-Nicene Fathers. Buffalo, NY: Christian Literature Company.

“And the Lord God formed man of the dust of the ground, and breathed into his nostrils the breath of life; and man became a living soul.” – (Genesis 2:7)